$-4pqr + 5q - 5r + 1 = 6q - r - 5$ Solve for $p$.
Combine constant terms on the right. $-4pqr + 5q - 5r + {1} = 6q - r - {5}$ $-4pqr + 5q - 5r = 6q - r - {6}$ Combine $r$ terms on the right. $-4pqr + 5q - {5r} = 6q - {r} - 6$ $-4pqr + 5q = 6q + {4r} - 6$ Combine $q$ terms on the right. $-4pqr + {5q} = {6q} + 4r - 6$ $-4pqr = {q} + 4r - 6$ Isolate $p$ $-{4}p{qr} = q + 4r - 6$ $p = \dfrac{ q + 4r - 6 }{ -{4qr} }$ Swap the signs so the denominator isn't negative. $p = \dfrac{ -{1}q - {4}r + {6} }{ {4qr} }$